Fluid pumping apparatus



9 Q KRUEGER 3,366,069

v FLUID PUMPING APPARATUS Filed Dec. 6, 1965 RESERVOIR Fig. 5

INVENTOR. LOREN L. KRUEGER I ATTORNEY United States Patent 3,366,069 FLUID PUMPING APPARATUS Loren L. Krueger, Minnetonka, Minn., assignor to Honeywell Inc., Minneapolis, Minn., a corporation of Delaware Filed Dec. 6, 1965, Ser. No. 511,683 Claims. (Cl. 103-120) ABSTRACT OF THE DISCLOSURE A roller vane pump with valve means controlling fluid flow through a passage from the space inward of the vanes to a low pressure area to control the pressure acting outwardly on the vanes. Disclosed in detail is a valving apparatus arranged to automatically close the passage when rotat-ive power is applied to the rotor and to automatically open it when the power is removed so that the pressure behind the vanes is relieved, they quickly retract, and allow fluid to flow backward through the pump.

This invention relates to fluid pumping apparatus and more particularly, to pumping apparatus utilizing a rotary vane pump.

Rotary vane pumps, per se, are old in the art and are used in many applications today. Such pumps utilize a plurality of vanes carried by a rotor. As the rotor is rotated each of the vanes moves outwardly, voiding a space in the rotor. A restricted connection is made between this space and the area ahead of the vane so that, as the rotor rotates, the vanes are urged outwardly by both centrifugal force and the force supplied by the pressure in these spaces. Generally, the output of a given pump is varied by varying the speed of rotation of the rotor. When the pump is used for supplying fluid pressure to an actuating device, the system customarily includes a dump passage with a control valve for returning the fluid to the reservoir when it is desired to return the actuator to its original position.

My invention contemplates the control of the pressure in the spaces inwardly from the vanes of a rotary vane pump to control the action of the pump in the fluid system in such a manner that no external dump passage is required. Valve means controls fluid flow through a passage connecting these spaces to a relatively low pressure area. This valve means is arranged to automatically close the fluid passage when rotative power is applied to the rotor and to automatically open the passage when the power is removed so that the pres-sure in the spaces behind the vanes is relieved when the pump is stopped. Thus, vanes will quickly retract and allow fluid to flow backward through the pump so that the necessity of a dump passage and external control valve is eliminated.

Various objects and advantages of this invention will become apparent upon reading the following detailed description of the invention with reference to the drawing wherein: FIGURE 1 shows schematically a hydraulic control system showing the rotary vane pump in longitudinal cross section taken generally along line 11 of FIGURE 2; FIGURE 2 is a horizontal cross sectional view of the rotary vane pump taken generally along line 22 of FIGURE 1; FIGURE 3 is a longitudinal cross sectional view of the rotary vane pump disclosed in FIGURE 1 modified to incorporate my invention; FIG- URE 4 is a fragmentary cross sectional view taken gen-.

erally along line 44 of FIGURE 3; FIGURE 5 is a greatly enlarged bottom view of certain elements of the pump disclosed in FIGURE 3; and FIGURE 6 is a cross sectional view taken generally along line 6-6 of FIG- URE 5.

FIGURE 1 discloses a hydraulic system having a fluid reservoir 10, a rotary vane pump 11 for pumping fluid from the reservoir to a load device 12, and a valve means 13 for controlling the operation of the pump in the system. Pump '11 includes a body or hon-sing which may include a base portion 14a, a central portion 14b and an upper or cover portion 140. Portion 14b has formed therein a generally cylindrical chamber 15 (see FIG- URE 2). Chamber 15 has an inlet 16, which maybe formed through body portion 140, entering at one side thereof and an outlet 17, which may be formed through base portion 14a, at approximately a diametrically opposed position. Disposed in chamber 15 is a generally disc shaped rotor 20 having a plurality of generally radially extending, angularly spaced, slots 21 formed therein. A generally cylindrical member 22 extends through the center of rotor 20 and acts as both a driving means and a mounting means for the rotor. It mounts the rotor for rotation in chamber 15, eccentrically with respect to the walls of the chamber, and also it provides an upper portion 22a which may be connected to an appropriate source of rotative power, such as an electric motor. Rotor 20 preferably has a height substantially equal to the height of intermediate body member 14b so that it slidably engages body portions 141; and 14c. Member 22 is an operative part of the rotor and may actually be formed as a part of it or it may :be connected to the rotor by appropriate means such as by the use of a ball 23 which has a portion extending into a cooperating slot in member 22 and another portion extending into a cooperating slot in the rotor. At its upper end, member 22 may be sealed with respect to the housing by appropriate means such as an O-ring 24.

Disposed in each of the slots 21 is a vane 25 which may take the form of a cylinder or roller disposed with its axis extending vertically in the slot. It is to be understood that other shapes of vanes may also be used without departing from the spirit of my invention. For reasons which will appear hereinafter, the cross sectional dimension of each of the vanes is slightly less than the width of the slot in which it is disposed. I

The pump includes means for connecting the inner part of the spaces 21 to an area of relatively low pressure, such as reservoir 10. As used herein, the term relatively low pressure means a pressure substantially lower than the output pressure of the pump when it is operated. A fluid passage 26 connects the inner portion of each of the spaces 21 to a central axial opening 27 in driving member 22. Opening 27 is intersected by a cross passage 30 which cooperates with an annular space 31 in housing portion 140. An appropriate pass-age 32 connects area 31 to the reservoir by an external conduit 33 which is shown schematically in FIGURE 1. This conduit has interposed therein a control valve 13 which controls the fluid connection between spaces 21 and the low pressure area. Control valve 13 may 'be a modulating valve having a plurality, or an infinite number, of control positions or it may be a simple on oif valve, according to the particular application of the device. By way of example, I have shown a simple, manually operable, needle valve for this purpose.

The output device or load device 12 is shown by way of example only and includes a power bellows actuator 40, acting upon an output member 41 and a return spring 42, acting in opposition to the bellows.

The operation of the structure is as follows. When rotor 20 is rotated, for example in a clockwise direction as seen in FIGURE 2, vanes 25 move outwardly in their slots due to centrifugal force. As indicated previously, these vanes are slightly smaller than the slots in which they are carried and thus, as the rotor rotates, they ride against the back edge of the slot and provide a restricted connection between the space 21 and the area immediately ahead of the vane. It is important to the operation of the pump that this provide a restricted connection rather than a substantially unrestricted one. As the rotor is rotated, the pressure in the spaces 21 thus becomes substantially equal to the pressure ahead of the vanes. Since the vanes convey fluid ahead of them from the inlet 16' and force it out of the outlet 17, the pressure in spaces 21 becomes substantially equal to outlet pressure. This pressure forces the vanes outwardly and into engagement with the wall of the chamber. Thus, there are two forces acting upon the vanes, centrifugal force and the force provided by the fluid pressure generated by the pump itself.

If the control valve 13 is closed, the pressure in spaces 21 remains substantially at outlet pressure. However, by varying the position of the needle valve, the connection between spaces 21 and the low pressure area at reservoir is controlled. If valve 13 is partially opened, the pressure in the spaces 21 is somewhat reduced since the connection between these spaces and the area ahead of the vanes is restricted. Under these conditions the pressure urging the vanes outwardly is reduced and the vanes do not transport as much fluid as would be transported if the pressure in spaces 21 were higher. Thus, the output of the pump can be controlled without varying the speed of rotation of the rotor.

Operation of pump 11 supplies pressure to bellows 40 causing the output member 41 to move in a direction to compress return spring 42. If valve 13 is closed and the rotor stopped, vanes remain out against the wall of housing member 14!) and act as check valves since the pressure in spaces 21 is substantially equal to outlet presure. However, a fast dumping action can be obtained, without the necessity of an external dump passage and control valve, by simply opening valve 13 to a position wherein it provides a substantially unrestricted connection between the inner portion of slots 21 and the low pressure area. As soon as valve 13 is opened, the pressure is relieved in slots 21 and vanes 25 move inwardly so that fluid can flow backwards through the valve from outlet 17 to inlet 16 to reservoir 10.

FIGURES 4 through 6 disclose a rotary vane pump modified to incorporate my invention. In this pump, a valve means is arranged to automatically close the fluid passage between spaces 21 and the low pressure area when rotative power is applied to the rotor and to automatically open the passage whenever this power is removed. This provides an automatic dumping arrangement without an external dump circuit and control valve. In the following description of the modification, those parts of the pump which are similar to parts in FIGURES 1 and 2 have been given identical reference numerals. In this embodiment, the main change is in the driving means for the rotor. This is provided by a pair of relatively movable members including a first hollow cylindrical member 50 which is an operable part of rotor 20 and may be formed as an integral part thereof or may be connected to the rotor by appropriate means such as ball 23, utilized in the structure previously described in connection with FIGURE 1. It is suflicient that member 50 be mechanically fixed to rotor 20 and also that a relatively good fluid seal be provided between the two. A second hollow cylindrical member 51, having a central opening or hollow 51a, is slidably disposed inside member 50. Member 51 is operably connected to a driving shaft 52 which is adapted to be connected to a source of rotative power (not shown) such as a rotary motor. Shaft 52 may have a downwardly extending transverse tab 53 which extends into a slot in the upper end of member 51 (see FIGURE 4). Members 50 and 51 are connected together by an angular lost motion connection so that they can rotate between first and second relative angular positions with respect to each other. This lost motion may be provided by a pin 54 disposed in a diametrically extending slot 55 in the under end of member 50. The under end of member 51 is formed with diametrically opposed recessed arcuate spaces 56 through which pin 54 extends. Thus, members and 51 may be rotated with respect to each other by an amount determined by the length of these recessed arcuate spaces. Pin 54 is held in place by a spring 57 disposed in hollow 51a of member 51 and having one end hooked around pin 54 and the other end hooked in an appropriate aperture in tab 53. Spring 57 not only maintains pin 54 in slots in the under end of member 50, but also acts as a torsion spring resiliently biasing members 50 and 51 to the angular position shown in FIGURE 5. This is accomplished since, as indicated previously, tab 53 is operably connected to member 50, connecting the upper end of spring 57 to member 50, while the lower end of the spring is connected to member 51 by means of pin 54.

Member 50 has a plurality of angularly spaced openings 60 therethrough, each connected to one of the passages 26 which in turn connects to the space 21 behind one of the vanes 25. These openings 60 cooperate with a similar plurality of openings 61 through the wall of member 51. When the two members assume the angular position shown in FIGURE 5, the normal position of the two members, openings 60 and 61 align to provide a substantially unrestricted connection between spaces 21 and central opening 51a in member 51. When the two members are moved to their other relative angular position, that is to the other end of their relative movement, these ports are substantially unaligned and interrupt the connecion between spaces 21 and opening 51a. Opening 51a is connected to an appropriate area of relatively low pressure, as for example by a passage 62 which is directly connected to inlet 16.

The operation of the pump disclosed in FIGURES 3 through 6 will be apparent in view of the above description. Briefly, when no rotative power is applied to shaft 52, members 50 and 51 assume the relative angular position to which they are urged by spring 57. In this position openings 60 and 61 are aligned and spaces 21 are com nected to inlet 16 and, consequently, to low pressure. When rotative power is applied to shaft 52, member 51 rotates clockwise with respect to member 50 until it reaches the end of angular recesses 56 at which time pin 54 is engaged by the lower end of member 51 and carries the pin and member 50 with it. At this relative angular position of the two members, the openings 60 and 61 are out of alignment and the fluid passage between spaces 21 and inlet 16 are substantially blocked. Thus, as rotor 20 is rotated, outlet pressure builds up in the spaces 21 urging vane 25 outwardly. However, as soon as the rotative power to shaft 52 is interrupted, rotor 20 will stop. Spring 57 (and perhaps the inertia of the device) will cause members 50 and 51 to assume their normal relative angular positions, thus aligning openings 60 and 61 and dumping the pressure in spaces 21 so that vanes 25 can move inwardly allowing the fluid pressure to dump backwards through the valve. In this manner, the structure provides an automatic dumping arrangement directly through the valve whenever the operation of the pump is stopped.

As has been indicated in the above description, the embodiment of my invention which has been described is intended for illustrative purposes only. Various modifications can be made thereto without departing from the invention and some of these modifications may become apparent to those skilled in the art in view of my disclosure herein. It will be particularly obvious that the valving arrangement provided by the relative movement of members 50 and 51 may be accomplished by various other valve arrangements operated in response to the application or removable of rotative power from the driving means for the rotor.

It is therefore to be understood that my invention is to be limited solely by the scope of the appended claims.

I claim:

1. In a rotary vane pump of the type having a plurality of vanes carried in angularly spaced slots in a rotatable rotor and which are moved outwardly from the center of rotation of the rotor when the pump is operated thereby voiding a space in the inner portion of the slots, means providing a restricted connection between each of the spaces in the area ahead of the corresponding vane when the pump is operated so that pressure generated by the pump urges the vanes outwardly, passage means adapted to connect the inner portion of each of the slots to a common area of relatively low pressure, and driving means for connecting the rotor to a source of rotative power, the improvement comprising: valve means operable between a plurality of control portions in the passage means for controlling a fluid flow therethrough; means operably associated with said valve means and responsive to application of rotative power to the rotor to operate said valve means to a first of its control positions and responsive to cessation of application of rotative power to the rotor to operate said valve means to a second of its control POSlLIOIlS.

2. The combination of claim 1 wherein said valve means substantially closes said fluid passage means in said first control position and opens said fluid passage means in said second control position to dump the fluid in said spaces so that the pressure in the area ahead of the vanes forces them inwardly into said slots allowing fluid to flow backward through the pump from the outlet to the inlet.

3. The combination of claim 1 wherein the driving means for the rotor includes two members connected by an angular lost-motion connection so that they are movable between first and second relative angular positions, the first of said members being connected to the rotor and the second adapted to be connected to the source of rotative power; wherein there is means resiliently urging said first and second members to their first relative angular position but yieldable so that upon application of rotative power to said second member said members assume their second relative position; and wherein said valve means is operably connected to said driving means so that said valve means assumes said first and second control positions when said members are in their first and second relative angular positions, respectively.

4. The combination of claim 3 wherein said fluid passage means is substantially closed to fluid flow when said valve means is in its first control position and wherein fluid flow through said passage means is substantially unimpeded when said valve means is in its second position.

5. The combination of claim 3 wherein the first member of said driving means is a hollow cylindrical member having a central opening which is adapted to be connected to an area of relatively low pressure and having a plurality of angularly spaced radial openings in its annular wall; wherein the second member of said driving means is an operative part of the rotor and has a cylindrical opening into which said first member is slidably fitted; wherein said passage means includes passages extending from the inner portion of each of the slots in the rotor and terminating in angularly spaced openings into the cylindrical opening in said second member; and wherein the openings in said first and second members are disposed so that they align when said members are in their second relative angular position and are substantially unaligned when said members are in their first relative position.

References Cited UNITED STATES PATENTS 1,749,121 3/1930 Barlow 103-136 2,411,602 11/1946 Tweedale 103l20 2,631,540 3/1953 Baugh et a1. l03136 2,670,689 3/1954 Ferris 103l36 2,716,469 8/1955 Gassot 103l20 DONLEY J. STOCKING, Primary Examiner.

WILBUR J. GOODLIN, Examiner. 

